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Discussion Starter #1
After 5 years, I guess the Honda bug bit me again. I restored a CB360 then, and it works nice now, but I always found it a bit lacking in power, and not really suitable for a longer trip.
So, today, in the morning, I bought a Honda CB450 DOHC. This engine always fascinated me. It shows innovation and some very nice solutions to certain problems, that even later motorcycles had. I saw it yesterday on a motorcycle swap-meeting/fair in Germany. After a day of bartering, we settled for a price and I brought it home. I know nothing about the motorcycle (the person who sold it was Italian and he understood only a few foreign words). I think it must be from 1971 or maybe later. It has a few dents and scratches, but it is still in a fairly original state. I will try to leave it as it is. The tank is surprisingly completely rust-free. I have started the bike an hour ago, and it started up very fast, but the fuel petcock/valve is broken, and the carbs soon started to leak if I left the fuel on. The carbs are in nice condition (incredibly easy to remove the float bowl and check, I wish they kept this BMW-ish feature on their other models, it only has a clip to hold it), I suspect they only need new seals (I hope the floats are not leaking). There was some clean oil in the engine, but I will change it before I start it another time (seems like the bike was standing for a long time, the tyres are surely from the 70's). The seat and the handlebar are not original, but I think it will not be that hard to find them.

So, what are the things I need to check on this bike? As far as I know, they did not have any engine problems (and the engine ran very quietly for the few minutes that it was running, so it seems fine). I have this on my list:
-cleaning the carbs, replacing the seals, checking the floats... (possibly without removing the carbs from the bike, the manifolds seem very good, but I suspect they could be problematic and expensive if they break while I am removing the carbs).
-cleaning and adjusting the points (and replacing them later on, but just cleaning them should do the trick for testing it), and the advance mechanism, and adjusting the ignition
-checking the valve clearance
-replacing the oil and cleaning the filter,
-replacing the tyres and the chain (the rear sprocket seems very small, maybe someone replaced it for low rpm),
-probably need to replace the fork seals and new fork oil,
-overhaul the front brake, with a new stainless steel line,
-spark plugs,
-replacement original old seat (do they fit from other models?) and handlebars,
-fit the rear turn signals (I probably have a spare pair),
-new rubber grips,
-I need to thoroughly check the cables for any damage (I don't want to replace them, they are original white and seem fine), and also a check of all other bolts and nuts,
-the exhausts are not original, and it will probably be very hard to find an original pair, so I will keep these for now (or maybe if I find a less rusted pair of nice mufflers).

I think that is more or less it. I want to make a list of things, and keep the costs to a minimum. I want to keep the bike original.

On the photo, the bike was still not cleaned. I will take some more photos tomorrow.

9rrlur.jpg
 

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After 5 years, I guess the Honda bug bit me again. I restored a CB360 then, and it works nice now, but I always found it a bit lacking in power, and not really suitable for a longer trip.
So, today, in the morning, I bought a Honda CB450 DOHC. This engine always fascinated me. It shows innovation and some very nice solutions to certain problems, that even later motorcycles had. I saw it yesterday on a motorcycle swap-meeting/fair in Germany. After a day of bartering, we settled for a price and I brought it home. I know nothing about the motorcycle (the person who sold it was Italian and he understood only a few foreign words). I think it must be from 1971 or maybe later. It has a few dents and scratches, but it is still in a fairly original state. I will try to leave it as it is. The tank is surprisingly completely rust-free. I have started the bike an hour ago, and it started up very fast, but the fuel petcock/valve is broken, and the carbs soon started to leak if I left the fuel on. The carbs are in nice condition (incredibly easy to remove the float bowl and check, I wish they kept this BMW-ish feature on their other models, it only has a clip to hold it), I suspect they only need new seals (I hope the floats are not leaking). There was some clean oil in the engine, but I will change it before I start it another time (seems like the bike was standing for a long time, the tyres are surely from the 70's). The seat and the handlebar are not original, but I think it will not be that hard to find them.

So, what are the things I need to check on this bike? As far as I know, they did not have any engine problems (and the engine ran very quietly for the few minutes that it was running, so it seems fine). I have this on my list:
-cleaning the carbs, replacing the seals, checking the floats... (possibly without removing the carbs from the bike, the manifolds seem very good, but I suspect they could be problematic and expensive if they break while I am removing the carbs).
-cleaning and adjusting the points (and replacing them later on, but just cleaning them should do the trick for testing it), and the advance mechanism, and adjusting the ignition
-checking the valve clearance
-replacing the oil and cleaning the filter,
-replacing the tyres and the chain (the rear sprocket seems very small, maybe someone replaced it for low rpm),
-probably need to replace the fork seals and new fork oil,
-overhaul the front brake, with a new stainless steel line,
-spark plugs,
-replacement original old seat (do they fit from other models?) and handlebars,
-fit the rear turn signals (I probably have a spare pair),
-new rubber grips,
-I need to thoroughly check the cables for any damage (I don't want to replace them, they are original white and seem fine), and also a check of all other bolts and nuts,
-the exhausts are not original, and it will probably be very hard to find an original pair, so I will keep these for now (or maybe if I find a less rusted pair of nice mufflers).

I think that is more or less it. I want to make a list of things, and keep the costs to a minimum. I want to keep the bike original.

On the photo, the bike was still not cleaned. I will take some more photos tomorrow.
Nice find. Here's a bit of info so you can figure out what year it is

cl450k4-6.jpg
 

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Check compression while you are at it. Nice bike by the way.
 

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After 5 years, I guess the Honda bug bit me again. I restored a CB360 then, and it works nice now, but I always found it a bit lacking in power, and not really suitable for a longer trip.
So, today, in the morning, I bought a Honda CB450 DOHC. This engine always fascinated me. It shows innovation and some very nice solutions to certain problems, that even later motorcycles had. I saw it yesterday on a motorcycle swap-meeting/fair in Germany. After a day of bartering, we settled for a price and I brought it home. I know nothing about the motorcycle (the person who sold it was Italian and he understood only a few foreign words). I think it must be from 1971 or maybe later. It has a few dents and scratches, but it is still in a fairly original state. I will try to leave it as it is. The tank is surprisingly completely rust-free. I have started the bike an hour ago, and it started up very fast, but the fuel petcock/valve is broken, and the carbs soon started to leak if I left the fuel on. The carbs are in nice condition (incredibly easy to remove the float bowl and check, I wish they kept this BMW-ish feature on their other models, it only has a clip to hold it), I suspect they only need new seals (I hope the floats are not leaking). There was some clean oil in the engine, but I will change it before I start it another time (seems like the bike was standing for a long time, the tyres are surely from the 70's). The seat and the handlebar are not original, but I think it will not be that hard to find them.

So, what are the things I need to check on this bike? As far as I know, they did not have any engine problems (and the engine ran very quietly for the few minutes that it was running, so it seems fine). I have this on my list:
-cleaning the carbs, replacing the seals, checking the floats... (possibly without removing the carbs from the bike, the manifolds seem very good, but I suspect they could be problematic and expensive if they break while I am removing the carbs).
-cleaning and adjusting the points (and replacing them later on, but just cleaning them should do the trick for testing it), and the advance mechanism, and adjusting the ignition
-checking the valve clearance
-replacing the oil and cleaning the filter,
-replacing the tyres and the chain (the rear sprocket seems very small, maybe someone replaced it for low rpm),
-probably need to replace the fork seals and new fork oil,
-overhaul the front brake, with a new stainless steel line,
-spark plugs,
-replacement original old seat (do they fit from other models?) and handlebars,
-fit the rear turn signals (I probably have a spare pair),
-new rubber grips,
-I need to thoroughly check the cables for any damage (I don't want to replace them, they are original white and seem fine), and also a check of all other bolts and nuts,
-the exhausts are not original, and it will probably be very hard to find an original pair, so I will keep these for now (or maybe if I find a less rusted pair of nice mufflers).

I think that is more or less it. I want to make a list of things, and keep the costs to a minimum. I want to keep the bike original.

On the photo, the bike was still not cleaned. I will take some more photos tomorrow.
Definitely a nice bike, and for not being washed it's pretty clean too. Good t hear you want to keep it original as well, that's a nice-looking year to do it with. the engine top end is a bit fascinating, I've always liked it. Ahead of its time in some ways. One thing to point out though, this engine is slow to get oil flow to the top end so on a cold start, be sure to let it idle (or keep it around idle speed) for at least a minute and a half to two minutes before revving it up. Other than that, just your usual maintenance stuff like all bikes from that era and it will likely treat you well. You're on the right track with the things you've mentioned. There's a list of stuff to look at here for the new owner of an old bike, it's a good read - one of the moderators will post the link.
 

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That a very nice find. I'm also glad you're going to try to keep it stock. Like Dad said, it's pretty nice without being cleaned. It is going to look great when it's "cleaned"! Congrats
 

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Discussion Starter #6
Finally a new update!
I tried making my own carb gaskets, but I guess they were not perfect. Original ones were very cheap, so I ordered them. When they finally came, the carbs no longer leaked. I replaced the oil. The bike starts nice and runs great. The engine is very quiet. I think its my first pre-80's bike where I did not have remove the carbs to clean them.
I also finally finished my R90S project, so I gues I will have more time for this.
 

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Discussion Starter #7 (Edited)
So, I cleaned the bike up, it seems to be in decent shape. I am slowly going over each part, fixing the problems and removing the rust, but trying to keep it stock...

The air filters are original, but the paper element was clogged and it had holes. Replacement filters are not cheap, and I fount out using the green UNI foam should work good. I ordered the foam on ebay, but I figure it will take a few weeks to come to Europe.
In the meantime, I decided I will remove the old paper element and glue. So, I started heating it up with a hot air gun. The old glue is very hard, and I guess I heated it up a bit too much in the end, because the paper element caught on fire.
hT6pQZI.jpg

To my surprise, the metal parts are not welded together, so the filter fell apart. If I did it again, I'd probably just leave them in a furnace for a bit. Fire might melt the mesh, but I am planning on replacing it anyway, since it is rusty and it bends way too easily. Fire would burn off everything, and you only have to clean it with a wire brush afterwards.
5TgPSK0.jpg

I will replace the steel mesh with a (maybe slightly thicker) stainless one, that will hold the shape better (this one melted very fast anyway).
IehxWQG.jpg


I think I will tack weld the spacer (where the bolt goes through) to the bottom plate, as well as the "front plate" (where the rubber for the carb goes in) to the bottom plate. The stainless mesh (once I buy it) will get tack welded on the front plate as originally, so only the top plate will be seperate. To hold the foam in, I am thinking about welding another layer of stainless mesh on the outer side, so that the foam will fit between two layers of stainless mesh, and the the top cover will slightly squeeze it together and seal the whole thing. Then, I will have it yellow zinc electroplated, so it will be hard to tell from original (and painting it would be a bad idea since fuel from the float bowls evaporates out through them when the bike is not running).
So, if all goes well, I will end up with a nice set of reusable air filters with a cleanable foam element which will be hard to distinguish from stock.
 

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I attached the mesh with a glue that builders use on wood. We call it liquid nails sometimes over here. Works good and easy.
 

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hot glue will work just as well and may even be easier to work with.
 

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Discussion Starter #10
I attached the mesh with a glue that builders use on wood. We call it liquid nails sometimes over here. Works good and easy.
I had that idea too, but I want it all to hold together when I have it electroplated. A few tack welds should hold it on very good... After spending my time cleaning that old glue off, I think I'll rather try to avoid it if I can. I also do not if just any glue would hold up in the air filter on the long term, as some fuel may evaporate in there...
 

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I had that idea too, but I want it all to hold together when I have it electroplated. A few tack welds should hold it on very good... After spending my time cleaning that old glue off, I think I'll rather try to avoid it if I can. I also do not if just any glue would hold up in the air filter on the long term, as some fuel may evaporate in there...
Holds up fine. I would think that'd be a tricky welding job and the costs would exceed new filters.
 

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Discussion Starter #12
Holds up fine. I would think that'd be a tricky welding job and the costs would exceed new filters.
Well, I do have a mig welder, and I think I will try to do it. If it burns through the mesh, I will probably just solder it in place. Although hot glue is not a bad idea either, I think I'll try how it holds up to fuel.
 

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Discussion Starter #13 (Edited)
So, I did some work on the filters...
I bought the stainless mesh, and cut it as original.

GAhK7AC.jpg

I also got the outer mesh in place
bJ9yZKb.jpg
I still do not have the foam, but I don't want it to be too tight, just so that the foam will not fall out.
I soldered it all in place, and it holds on very good.
gjPm7rJ.jpg

2wcut1E.jpg


The plastic cover goes over it okay. I still need to do the other one...
ZRjHGnE.jpg

I think it looks very neat.

Qij3MuW.jpg

I think I will weld on a long nut on the inside, and add a bolt to hold down the top cover through another hole, so that when I remove the side cover, it will not all fall apart (and it will be easy to assemble seperately as well). After I do the other one, I just have to have all the parts yellow zinc plated, and it will look nearly original.
 

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Discussion Starter #14 (Edited)
So, I did not update this thread for some time now.
I finished the filters, and inserted the foam. It was a bit hard to get it between the mesh, but it looks neat when together. I did not take any photos of it assembled, mainly because my hands were all oily because of the foam.
If you want to keep stock filters, and do not want to spend a fortune for them, this is a great solution. If I did it again, I'd only use one mesh wall, not two, as it is really hard to get the foam in between. I think only one mesh (as stock) and a bit more wide foam strip would work just as well...


I've bought an original used seat in awesome condition from ebay. I still need to cut off the brackets which the previous owner welded to the frame, so he could use the cruiser seat (I found out it was actually a Moto Guzzi V50C seat).
TQpxdOn.jpg
As you can see from the photo, I've also replaced the tall handlebars for some low japanese bars. They may be a bit more low than originally, but I like it. So, the bike looks quite decent now. I still need to find original mufflers (the current italian ones do not look too bad either, but are a bit rusty). Also need the rubber fork gaiters, and I need to replace the ancient rubber brake lines. I want to keep it stock, but I hope stainless braided lines are not considered bad (if not just for show use), even by most purists. A friend makes then, and I can get them for nearly free any way, and I will probably find some thick black rubber tube to put over them, so they will look stock (exposed lines are notorious for cutting into anything they rub against). Otherwise, the bike is ready to go on the road (but some new tires would not hurt either, and of course a battery... and oil... oh well, there's always something).


Also, it is really funny to see how much more low the Guzzi bikes were, since their Tonti frame main tubes go in between the "V" of the engine. You do not really notice it until you sit on it or place it next to another bike.
 

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Very nice 450. BTW- I love the DOHC 450. Your bike looks like a K5. Those were sold in the US as a 1975 model. Seat is fantastic. Left side mufflers in good condition are hard to source. It seems many bikes rolled off the side stand and dented it. You will find all of the dented mufflers are dented in the same area. One of the British suppliers (maybe David Silvers Spares) was making reproduction mufflers. They were very close to the orignals at about $600US. Keep working and keep us posted.
 

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Discussion Starter #17
Very nice 450. BTW- I love the DOHC 450. Your bike looks like a K5. Those were sold in the US as a 1975 model. Seat is fantastic. Left side mufflers in good condition are hard to source. It seems many bikes rolled off the side stand and dented it. You will find all of the dented mufflers are dented in the same area. One of the British suppliers (maybe David Silvers Spares) was making reproduction mufflers. They were very close to the orignals at about $600US. Keep working and keep us posted.
Hm, in that case I will likely just stick to the old Italian aftermarket mufflers it already has. They still look alright, and they give a nice deep sound too.
I actually wanted to use an Italian Honda CB750 Four aftermarket Giuliari seat, like this one:
honda_cb750_giuliari_seat_04.jpg
Of course, I'd somehow try to remove the 750 four sign.
With the low bars and aftermarket exhausts, it would look a bit 70's cafe racer-ish (so, still fairly period-correct). Replicas of these seats are still made.
But I that I found a stock seat (and for a good price too), and it is also wonderful...
 

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Discussion Starter #18
So, I have a question regarding the CB450 cam chain tensioner(s). My experience with the CB360 was not too good regarding this. It had the first version, and it failed on me (luckily it did not cause any real problem, apart from the need to replace it with a recalled one). I remember I paid a lot for a NOS item, and just when I installed it, cheaper aftermarket ones (probably made of better modern material) appeared.

So, my question is, were CB450 tensioners also problematic? Can I just unscrew it from the cylinder, and inspect it (or would that cause problems)? The small wheel tensioners seem very simple to make (compared to the CB360 long springy tensioner), so I hope aftermarket ones are not as expensive. If I can replace it without removing the cylinder head, should I do it?
 

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You can take them off for inspection. It's a big rubber wheel that can get worn. I've never had one fail, but.....
 

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Discussion Starter #20 (Edited)
So, I've finally fit the seat, and sorted out most other things as well. I'll try to register it tomorrow. She looks magnificent!

I have a problem with the front disc brake (started to wish it was a simple drum as on older models). The piston had some rust, so I've actually made a soild stainless one. It's a bit heavier, but I think it'll do (could hollow it out and put a cap on the end like stock, but it was just easier leaving it full). I hope stainless will not react with aluminium caliper. Main thing is that it will be sorted once I get the seal. I hope I will not have to disassemble the master cylinder, although it is probably quite bad too (but I do not have the pliers to remove the circlip). I also have to replace the brake lines. I know stainless is a lot better, but I think I'll stick with rubber because it just fits better on such an old bike (it will not be my "main" bike either way...).


I've also adjusted the valves, ignition and the cam chain (actually in reverse order). Adjusting the valves is quite problematic, and now I understand why new bikes do not do it this way anymore. Turning it just the slightest bit changes it considerably. I've adjusted them to 0.05mm, while stock should be 0.03mm, but I think it'll be fine. Previously it had 0.15mm of play, so the engine is now completely quiet. Really makes me nervous, most modern bikes are definitely louder, the engine hardly makes any mechanical sounds at neutral, you only hear the exhaust note.
 

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